The present invention relates to a method for manufacturing a semiconductor device of mesa type.
According to the conventional method for manufacturing a semiconductor device of mesa type, a P-type semiconductor layer 3 is formed on an N.sup.+ -type semiconductor layer 1 with an N-type semiconductor layer 2 interposed therebetween. After an N.sup.+ -type impurity region 4 is formed at a predetermined region in the P-type semiconductor layer 3, an insulating layer 5 is formed on the surface of P-type semiconductor layer 3 to form a predetermined element. Mesa recesses 6 are then formed by chemical etching or blade dicing at predetermined regions of this element, each of mesa recesses 6 having a depth passing through the insulating layer 5, P-type semiconductor layer 3 and N-type semiconductor layer 2 into the N.sup.+ -type semiconductor layer 1 and reaching a predetermined depth in the N.sup.+ -type semiconductor layer 1 (see FIG. 1A).
Fine glass powder 7 mixed with organic solvent is filled in mesa recesses 6 by electrophoresis or the like (see FIG. 1B).
Glass powder 7 filled in the mesa recesses 6 is heated and sintered to form glass insulators 8, thus enabling a semiconductor device 9 of so-called mesa type to be obtained (see FIG. 1C).
However, in the case of this semiconductor device 9 thus manufactured, stress was concentrated in the semiconductor substrate provided with the element or in the glass insulators 8 causing cracks to form. As the result, the property of the element was so degraded as to make the element non-usable.
This concentration of stress is caused by the reason that the volume of glass powder 7 is reduced when it is sintered to form the glass insulators 8 as shown in FIG. 1C. Therefore, taking into account the volume reduction of glass powder 7, an excess volume of glass powder 7 is filled in the mesa recess 6 as shown in FIG. 1B. However, it was extremely difficult to accurately fill glass powder 7 into mesa recesses 6 taking into account the volume reduction of glass powder 7. In addition, the form of glass powder 7 filled was made irregular, thus making it impossible to completely prevent the concentration of stress.